29 March 2020

A Tale of Two Kings

A Tale of Two Kings
Featuring : The King Crow and Palm King

Two Kings amongst the Singapore butterfly fauna

Whenever the title of "King" is conferred to a person, a thing or an animal, it bestows on the holder a large measure of high regard or an expectation of being preeminent in its class. A King in the human world describes a ruler of people and territory - a leader, a sovereign or a monarch, inherited by birthright or by conquest. Used as an adjective, it suggests superiority over the normal, due to sheer size, influence or magnificence.

Various poses of the King Crow

In the butterfly world, there are a number of species that have been given the common name of "King" by the early collectors and authors. Of these, two can be found amongst the butterfly fauna in Singapore. Whether these species deserve this majestic name or not, is subject to debate, but over the years, they have been regularly called by their respective names that have remained in common use by butterfly enthusiasts.

Palm Kings are more likely to be spotted perched in the well shaded forests in Singapore

Both these species are notable for their larger size in relation to other related species in their sub-families. Although they are rather drab butterflies, their presence in the environment is very obvious as they fly around in their respective habitats. Both these species are not uncommon, and generally observed in localised areas where they frequent - usually in the vicinity of their caterpillar host plants and preferred habitats.

The King Crow (Euploea phaenareta castelnaui)

A King Crow feeding on the flower of Lantana camara

The first of our "Kings" is the King Crow (Euploea phaenareta castelnaui). Also called the Great Crow in certain regions, this species is the largest in its genus Euploea, of which 8 species have been recorded in Singapore. The King Crow frequents mainly mangrove and back-mangrove environments where its caterpillar host plant, the Pong-Pong Tree (Cerbera odollam) can usually be found. It is a resilient butterfly and has a large mobility index where it can fly long distances to other habitats in search of food.

There was a time when the Pong-Pong Tree was cultivated along roadsides and in urban parks and gardens as a shade tree. However, the damage caused by its large round fruits dropping onto parked cars and also the fact that this lactiferous tree has a poisonous sap that may be harmful to humans and pets has made it less desirable as a roadside tree in recent years. However, it still grows commonly in mangrove areas like Pasir Ris Park mangroves and Pulau Ubin.

A female King Crow feeding on the flower of the Buas-Buas

The King Crow is a slow flyer, making its presence felt by its sheer size as it glides by unhurriedly at treetop level. It is one of the distasteful Crow species that predators, like birds and reptiles, usually avoid. Its typical colour combination of black wings with white spots of the Danainae is a form of aposematic colouration that predators recognise.

A King Crow feeding on the flowers of a String Bush

The King Crow has large violet-tinged forewing apical spots sets it apart from the lookalike Malayan Crow. On the male, there is a raised scent patch on the hindwing cell and tornal area. The tornal area has a purplish sheen when viewed in a sidelight. The dorsum of the forewing of males are bowed, whilst it is straight in the females.

The Palm King (Amathusia phidippus phidippus)

The 2nd "King" that lords over Singapore's butterfly scene is the Palm King (Amathusia phidippus phidippus). The genus comprises a number of similar-looking species that are not easy to identify. All the species are large, usually shy and most are rare. The only common species that is most likely to be encountered by the butterfly enthusiast is the Palm King.

A Palm King perched on the leaves of a Coconut Palm, its caterpillar host plant

The Palm King is usually found in heavily shaded areas in the vicinity of its caterpillar host plant, the Coconut Palm (Cocos nucifera). It is attracted by overripe fruits and is sometimes encountered puddling on decomposing matter on the forest floor. It is a large butterfly, and is very conspicuous when it takes off in the habitats where it can be found.

A visiting Palm King perched on the wall of a HDB residential apartment block

The species is crepuscular in habit, and is attracted to lights of houses, and sometimes in urban Singapore, to the well-lit corridors of our HDB high rise apartments. There have been observations of pristine individuals perched on the walls of high rise residential areas, especially in the late evening hours of the day.

A Palm King perched on a twig

The Palm King is a medium brown on the upperside and usually unmarked. The underside is patterned with broad reddish-brown bands and narrower whitish bands across both wings. The hindwing features two large white-centred ocelli. The tornal area is blunt and has a pair of false "eyes".

A potential 3rd King in Singapore?

Recently, a possible 3rd "King" appeared in the form of a related species, the Bicolor-Haired Palm King (Amathusia friedrici holmanhunti). The key identifying attribute of this species are the abdominal hair tufts which are bicoloured, as compared to the Palm King's unicolourous hair tufts. It is hoped that a voucher specimen that will settle the doubt can be acquired soon. Until then, we have, for certain, two "Kings" in the butterfly world in Singapore.

Text by Khew SK : Photos by Alan Ang, David Chan, Khew SK, Huang CJ, Lim CA, Loh MY and Jonathan Soong

21 March 2020

Lepidoptera exotica

Lepidoptera exotica : The Non-Natives
Exotic butterfly species in Singapore

An "exotic" species in Singapore, the Great Orange Tip 

Recently, I attended a workshop conducted by NParks to discuss the definitions and clarify questions about various categories that are defined in the IUCN guidelines on threatened species. The workshop was held for the team leads and assessors of the forthcoming 3rd Edition of the Singapore Red Data Book. The Singapore Red Data Book conforms to the IUCN Red List of Threatened Species but is focused specifically on Singapore's biodiversity.

The IUCN status categories in the Red List

A group of over 60 experts and taxonomic leads/assessors from academia, government organisations and the public, specialising in various terrestrial and marine groups were there to share experiences and views on the Red Data Book.  The workshop session was to help standardise how we were going to assign categories and status of the various species in our respective taxonomic areas of interest.

Some controversial categories that were debated at the Workshop

Amongst the different classifications and categories discussed, was how to consider indigenous (native) species vs exotic (non-native) species. In many cases, some of our exotic butterfly species have been "naturalised" and have established viable and sustainable colonies in Singapore. In our human world, perhaps it could somewhat be comparable to a foreigner who has lived here for many years, became a permanent resident and then took up Singapore citizenship - what is often referred to as a "naturalised Singaporean".

Another non-native species found in Singapore, the Malayan Jester

Hence do we consider "naturalised" species as native? And how long should they be "naturalised" before we take them as native? Eventually, it was decided that only native species will be assessed (irrespective of whether they are naturalised or not) while non-native species will be excluded unless they are of conservation concern, but they will be placed in a separate holding section. For the butterfly group, the question that remained was, so which species is native and which is non-native?

The Pale Grass Blue can be considered a "naturalised" exotic in Singapore, having been continuously seen in urban parks and gardens since it was first discovered in the early 2000's

Native (indigenous) is described as "naturally existing in a place or country rather than arriving from another place" or "produced, growing, living, or occurring naturally in a particular region or environment. On the other hand, a non-native (exotic) species is one that "relates to a plant or animal that is not indigenous to a region" or "an organism that living or growing in a place that is not the location of its natural occurrence."

A mating pair of Tawny Costers, an exotic that was first discovered here in 2006

Whilst the definition of native and non-native is easy to understand, the challenge is the reference baseline information. For butterflies, we have often turned to the checklists that were produced by the authors of "Butterflies of the Malay Peninsula" and "Butterflies of West Malaysia and Singapore". These checklists made reference to data from collections that dated back to the late 19th century and are used as the baseline for the definition of what species is "native' or occurred naturally in Singapore.

The Yellow Palm Dart was discovered around 2009 and is now considered common in Singapore

Let us take a look at some of these "exotic" species in Singapore, and their status based on the IUCN guidelines, if they were to be assessed. These species are deemed as non-native as they were never recorded in Singapore before, based on our reference baseline checklists.  Other than Riodinidae, all the other five families of butterflies have examples of what is non-native in Singapore.

1) The Common Jay (Graphium doson evemonides) - IUCN : Vulnerable

The non-native Common Jay was discovered in 2004, and there is a resident population on Pulau Ubin

The Common Jay was not listed in the reference checklists of the early authors and thus far, we have had no evidence of its having been captured in Singapore in the reference collections that correspond to the checklists. It was hence a "new discovery" for Singapore when it was first spotted on the offshore island of Pulau Ubin in 2004. Over the years, however, there is a sustainable colony of the species on Pulau Ubin, and continues to be seen to this day.

Given its continued presence in Singapore, the Common Jay may be assumed to be a naturalised exotic to Singapore. As it has been bred on a variety of caterpillar host plants, amongst which are Desmos chinensis, Michelia alba and Polyathia longifolia, the species has a higher chance of sustaining its existence as part of Singapore's butterfly biodiversity. However, being a non-native species, it would be excluded from being assessed for the Singapore Red Data Book 3rd Edition.

2) The Great Orange Tip (Hebomoia glaucippe arturus) - IUCN : Endangered

The Great Orange Tip is a relatively large butterfly and has a strong flight. It was recorded from Singapore near one of our reservoir parks in the early 2000's. Several reported sightings were made on the island of Pulau Ubin in subsequent years. The sightings of this non-native species were probably of vagrant individuals that made it south to Singapore carried over by prevailing winds.

The Great Orange Tip is also a feature species in butterfly parks and individuals seen in Singapore could also have been escapees from these aviaries. This non-native is rarely seen in recent years, and will not be assessed for the Red Data Book 3rd Edition.

3) The Tawny Coster (Acraea terpsicore) - IUCN : Least Concern

First recorded as a new discovery to Singapore in 2006, the Tawny Coster is common here today, and continues to be seen regularly in urban and suburban areas. It has several alternative caterpillar host plants, and is hence able to maintain a sustainable population in Singapore for the past 14 years. It is also considered naturalised and is part of our urban biodiversity in Singapore.

The exotic Tawny Coster is now a naturalised species in Singapore, where it is common in urban areas

This slow-flying species is known to be distasteful to predators and that adds to its tenacity to survive and thrive in Singapore. Another naturalised species, the non-native Tawny Coster is likely to stay for the long term and has even widened its range to as far south as Australia in recent years.

4) The Malayan Jester (Symbrenthia hippoclus selangorana) - IUCN : Endangered

A small colony of the Malayan Jester survived at the Dairy Farm Nature Park for some time.

An individual of the Malayan Jester was first recorded as a new discovery for Singapore when it was spotted in 2012. The species was considered a possible vagrant until in the past 3-4 years when a colony established itself at the Dairy Farm Nature Park area. Whether the population can be sustained to qualify this species as a naturalised species remains to be seen.

Unlike other non-native species that have become common in Singapore, the appearance of this species has been erratic. However, where it occurs in Malaysia, the species is not uncommon. However, its appearance in Singapore would classify it as a non-native species and will not be assessed for the Singapore Red Data Book 3rd Edition.

5) The Pale Grass Blue (Zizeeria maha serica) - IUCN : Least Concern

This small butterfly was discovered here in the early 2000's, and was validated by the late Col John Eliot. The species was included in his Malayan Nature Journal : Update to C&P4 paper. The species has been considered extant in Singapore since the early 2000's and continues to be found here as a relatively common species. An individual was photographed at the Bt Panjang Butterfly Garden as recently as last weekend.

This naturalised species is relatively common, and in areas where they fly, there can be as many as 6-12 individuals fluttering around the grasses and wild flowers. Its caterpillar host plant, the Yellow Sorrel (Oxalis corniculata) is a common "weed". The Pale Grass Blue would be considered as "Least Concern" under the IUCN guidelines, but is still classified as a non-native species in Singapore and will not be assessed in the Singapore Red Data Book 3rd Edition.

6) The Yellow Palm Dart (Cephrenes trichopepla) - IUCN : Least Concern

A species that is more associated with the Australian region than Southeast Asia, this species first appeared in 2009 in Singapore. Since then, it has also moved northwards and has been spotted in West Malaysia. The fact that the common coconut palm (Cocos nucifera) is its caterpillar host plant may explain its rapid spread across the region.

This exotic species has now become common and is regularly seen at urban parks and gardens where the coconut palm can be found. It was even recorded from the offshore island of Pulau Semakau during our surveys conducted for the National Environment Agency on the island.

Participants at the Red Data Book 3rd Edition Workshop organised by NParks

And so, here we see a small sample of the exotics or non-native butterflies of Singapore. Some have become naturalised and common, whilst others continue to be elusive or probably vagrants. There are many other species that are exotic to Singapore, and they will not be assessed and featured in the main section on butterflies in the Singapore Red Data Book 3rd Edition.

Text by Khew SK : Photos by Khew SK, Loh MY, Jonathan Soong and Anthony Wong

14 March 2020

Favourite Nectaring Plants #17

Butterflies' Favourite Nectaring Plants #17
The Globe Amaranth (Gomphrena globosa)

A male Plain Tiger feeding on the flowers of the Globe Amaranth

Adding on to our series of butterflies' favourite nectaring plants, we take a look at a non-native flowering plant called the Globe Amaranth (Gomphrena globosa). In Singapore, it is not very widespread in gardens, but sometimes cultivated as an ornamental plant in landscaped areas and community gardens. The very characteristic and recognisable magenta pom-pom shaped inflorescence is a dominant and attractive feature of the plant.

The Globe Amaranth is an edible plant from the family Amaranthaceae. The plant grows upright, attaining a height of 0.3 - 0.6m tall and a spread of about 0.3m. It is considered a low shrub and often cultivated in pots too. It flowers throughout the year and usually does best in open areas in full sunshine. It is an exotic and it does not occur naturally in Singapore and where it grows, it has usually been cultivated.

Globe Amaranth plants at a community garden in Singapore

The Globe Amaranth is considered a non-native plant in Singapore. Its region of origin is Central America including regions of Brazil, Panama, and Guatemala. Its presence in Singapore is limited to urban parks and gardens, usually cultivated an accent shrub for its colourful flowers in combination with other flowering plants.

The pretty magenta inflorescence of the Globe Amaranth

As a tropical annual plant, the Globe Amaranth blooms continuously throughout the year. It is very heat tolerant and fairly drought resistant, and grows best in full sun with regular moisture. As the plant flowers and grows older, it is likely to look lanky and unattractive. It is then time to cut it down and let it sprout new shoots to regenerate growth again.

Plant Biodata:
Family: Amaranthaceae
Genus : Gomphrena
Species : globosa
Synonyms : Gomphrena rubra
Country/Region of Origin : Central America
English Common Names : Globe Amaranth, Bachelor's Button, Thousand Day Red,
Other Local Names : Makhmali, Vadamalli, 千日红

The Globe Amaranth is a compact herbaceous annual that typically grows to about 0.3 to 0.6m tall on upright branching stems. The plant is tolerant of most well-drained soil of moderate fertility, but appreciates regular moisture. However it is important not to overwater it. It grows and blooms best in full sun and is a drought-resistant plant.

The oblong and hairy leaves of the Globe Amaranth

The leaves are opposite and oblong to elliptical in shape (2–13 cm long, 0.5–5 cm wide). They start out wooly-white when young, but lose this characteristic as they age but turn deeper green with sparsely white hairs when matured. The mid-rib of the leaves can sometimes be tinted magenta, as do the stems.

The inflorescence of the Globe Amaranth on its long upright spike

The pom-pom shaped inflorescence are a visually dominant feature of the Globe Amaranth and cultivars have been propagated to exhibit shades of magenta, purple, red, orange, white, pink, and lilac. The inflorescence grows on a long upright spike.

Pink and magenta cultivars of the Globe Amaranth

Within the flowerheads, the true flowers are small and inconspicuous, with white to yellow trumpets that are only visible close up. It is the bright magenta bracts arranged in globose, papery-textured, clover-like flowerheads that provide the real show.

Seeds and young seedlings of the Globe Amaranth

The fruit is a bladderlike pericarp and is unopened at maturity and about 1.5–2.5 mm long. Seeds are shiny reddish brown, reniform, 1.5–2 mm wide and encased in a thick coating. New plants can be propagated by seeds quite easily, or through cuttings from older plants.

The attractive magenta inflorescence of the Globe Amaranth.  Note that the actual trumpet-shaped flowers of the plant are small and yellow

The dried inflorescence retain their colour well, and is often used in flower arrangements and decorations at weddings, as accent colours in wreaths and in artwork. The plant is also known to have various medicinal properties and is used for its antibacterial and antifungal properties and as an antioxidant.

Globe Amaranth cultivated in pots

Apart from the mentioned medicinal uses, it has been traditionally used for treating gall stones, nose bleed, and cough. It is a remedy for several respiratory inflammation conditions including bronchial asthma, acute and chronic bronchitis, and whooping cough. It has been traditionally used for reducing high blood pressure and blood sugar levels and this use has been proven through clinical research.

Some species of butterflies visit the flowers of the Globe Amaranth for its nectar. Whilst the flowers are small and the nectar contained within the flowers are probably very limited in quantity, it is surprising that we have seen some relatively large butterfly species feeding on them. We would have expected the smaller Lycaenidae and Hesperiidae to be the main visitors of this plant.

A Plain Tiger feeding on the flowers of the Globe Amaranth

At a community garden, a Plain Tiger was feeding on the flowers of the Globe Amaranth. Whilst this individual had other nectaring choices nearby, like the Purple Snakeweed and Mexican Sunflower, it still chose the Globe Amaranth for its nectaring source. It stayed for quite a long while, moving from flower to flower to feed.

A Tawny Coster feeding on the flowers of the Globe Amaranth

A Peacock Pansy feeding on the flowers of the Globe Amaranth

Two other Nymphalidae, a Tawny Coster and a Peacock Pansy, were also spotted feeding on the flowers of the Globe Amaranth. These are medium sized butterflies that would probably need to feed on many flowers to get an adequate supply of nectar relative to their size.

A Cycad Blue perches on the inflorescence of the Globe Amaranth after feeding on the flowers

A skipper, probably a Small Branded Swift, stopped to feed on the flower of the Globe Amaranth, whilst a skittish Cycad Blue moved from flower to flower and eventually perched on the magenta inflorescence to rest after a period of feeding.

A Peacock Pansy with its proboscis probing into the flower of the Globe Amaranth for nectar

It is likely that a good range of urban butterflies can use the Globe Amaranth as a nectaring source. Hence, this plant could be another species that can be included in the landscaping palette of a butterfly gardener's choice of nectaring plants when designing and planting a butterfly garden.

Text by Khew SK : Photos by Khew SK and Lim CA.